| 摘要 |
<p>1,180,795. Polyamines; polyisocyanates. MOBAY CHEMICAL CO. 4 Aug., 1967 [5 Aug., 1966], No. 36017/67. Heading C2C. [Also in Division C3] A process for the preparation of polyamines by condensing at 20-350‹ C. (a) an aromatic amine having 1 benzene nucleus and/or 2 NH 2 groups, with (b) CH 2 O or a precursor thereof or a suitable C 3-13 ketone, in presence of (c) an acid catalyst having a pKa in water at 25‹ C. of up to 5, is characterized by recycling 1-20% of the initial polyamine product with starting materials (a) and (b). A neutral salt may be used as an additional ingredient. In examples, CH 2 O containing HCO 2 H is reacted with PhNH 2 with the optional addition of NaCl to give a product containing 55% diamine, 25% triamine and 20% tetra- and higher amines, of formula where n = 0À85, and this product is phosgenated to give the corresponding polyisocyanate mixture.</p> |
